As increasing of a large amount of data transmission, requirements of bandwidth on the network are gradually advanced. To reach the requirements on network bandwidth, there are many transmission tools produced, which as ISDN modem, cable modem, asymmetrical digital subscriber line (ADSL), etc, wherein ADSL is the most type to be used for a wideband transmission.
Each transmission type has its own encoder and decoder for its convenience and speed. Talking about ADSL, general affair is to individually install a memory device to an ADSL encoder and an ADSL decoder. The memory device stores a constellation diagram when encoding and decoding. While the ADSL encoder/decoder encoding/decoding data for transmitting/receiving, encode/decode parameters comparative to constellation diagrams in the memory devices shall be found according to at the time of encoding/decoding conditions. After the encoding/decoding parameters being found, data for transmitting/receiving just can be processed for continuing encode/decode process.
As a conclusion, the prior arts of encoder and decoder are to install storage devices having constellation diagrams firstly; the encode/decode process is then executed after the comparative encode/decode parameters being found.
Based on the aforesaid issues, the present inventor of the patent has being studied and referred to practical experiences and theory for designing and effectively improving the prior arts.